1. Field of the Invention
The present invention relates to a display device, a display method and an image forming apparatus, and more particularly, to a display device and a display method for displaying options representing function items, and the like, of various machines, and an image forming apparatus (provided with the display device).
2. Description of the Related Art
Conventionally, various image forming apparatuses such as digital copiers, facsimile machines, printers, and the like, which are provided with a display device such as a so-called touch panel type display device at a user operation section thereof have been proposed. On this display device, particularly on the touch panel type display device, buttons and keys representing previously set function items of the image forming apparatus and a plurality of options associated with the functions are displayed. When a user selects, i.e., presses a desired button or key among these buttons and keys, the user can make the image forming apparatus execute various operations, can set various functions, or can instruct processing or execution of various functions.
By the way, buttons and keys displayed on a display device differ according to the number and types of functions and modules which can be added to an image forming apparatus on which the display device is provided. Usually, buttons and keys are designed and implemented based on the assumption that an image forming apparatus is provided with all of these additional functions and additional modules. Display positions of these buttons and keys on a touch panel are also determined based on the same assumption.
Therefore, if an image forming apparatus is one to which a so-called duplex copy function, which enables producing simplex copies from simplex originals, duplex copies from simplex originals, duplex copies from duplex originals, and simplex copies from duplex originals, can be added, and if the apparatus is provided with all of the additional functions, a display on a display device on the apparatus is such as shown in FIG. 10.
However, if an image forming apparatus is provided, for example, with only the copy functions from simplex to simplex and from simplex to duplex in the duplex copy function, and is not provided with the copy functions from duplex to duplex and from duplex to simplex, a conventional display device (on the apparatus) does not display the keys for the functions which have not been added, and merely displays the keys for the added functions in their original positions without any modification, as shown in FIG. 16. That is, when the display device is set to be able to display a plurality of buttons and keys, if some of functions corresponding to some of these buttons and keys are not added to the image forming apparatus, the conventional display device is designed such that the buttons and keys for the functions which are not added are simply not displayed, and no attempt has been made to adjust or change the display positions of the buttons and keys. Therefore, positions on the touch panel on which relevant buttons are not displayed are just left blank, which makes the display appear as if something is missing. If such a display is displayed on the display device, appearance of the display device is not pleasing.